1. Field of the Invention
The invention relates to a method and composition for treating Herpes Zoster Varicella (“shingles”) and the consequential Postherpetic Neuralgia (PHN). More particularly, the invention relates the treatment of shingles and PHN with anti-viral proteins extracted from pokeweed plants.
2. Description of the Prior Art
In the United States alone, Herpes Zoster Varicella, that is, shingles, affects about 1 million people each year with new cases. Even after the initial infection has been treated, the lingering pain and nerve dysfunction (Post Herpetic Neuralgia—) PHN continues to disturb millions of affected individuals for years. In fact, PHN can be so severe and last for so many years that it is considered a significant factor in suicide for sufferers.
The Varicella Zoster virus, as it manifests itself in shingles, is thought by many to be a re-expression of the childhood disease chickenpox. It has some strong similarities to chickenpox, such as, the appearance of the lesions and the usually once-per-lifetime emergence of the disease. However, there are differences as well. Shingles is caused by the Varicella Zoster virus emerging from dormancy, where it inhabits the nerve ganglion and travels out along the nerve cells until it reaches the skin. Once at the skin, it imbeds itself within the DNA of the skin cells and forces replication. This causes the virus to be replicated. One key difference between chickenpox and shingles is that during the process of nerve migration and replication of the shingles virus, the myelin sheaths of the nerves themselves are damaged when shingles strikes an individual. This damage leaves the sufferer with a highly disturbing sense of tingling along the nerve. In some cases, the damage causes unbearable pain.
People have studied whether shortening the duration of a shingles outbreak leads to a recovery involving less PHN (although there is no known mechanism for consistently shortening the duration). However, any potential correlation has been poorly demonstrated at best.
Shingles is generally accepted as being a viral infection. Current teachings suggest treatment by the administration of an oral anti-viral. At present, the most popular systemic antiviral seems to come from the Acyclovir family or Pencyclovir family. Drugs from these derivatives, when supported with a mechanism to aid in systemic transfer through the digestive system, are intended to reduce the activity and replication of virus throughout the body.
The clinical data shows remarkably poor efficacy when this drug therapy is initiated more than 48 hours after initial symptoms are recognized. When the drug therapy is implemented within the first 48 hours, the response tends to be inconsistent and may offer good results in some subjects and very poor results in other subjects. The treatment process is further complicated as only a small percentage of the cases are identified and treated within the first 48 hours of the onset of symptoms.
Potent systemic anti-virals, such as those of the Acyclovir, Pencyclovir or Famcyclovir families, are only given for a short period of time since long-term administration of the cyclovir derivatives has been associated with renal damage. Additionally, there is no efficacy shown in continued administration beyond 7 days for Famcyclovir (FAMVIR), nor has any efficacy been established for occular involved (opthalmic) zoster.
Unfortunately, a shingles out-break typically endures for 4 to 6 weeks. After this time there is a significant period of healing to repair the damage done to the skin tissues. Even after this period of healing passes, subsequent PHN can last for months to years. Clearly, a short course of anti-virals that doesn't sufficiently quell the outbreak is not an acceptable solution.
Recently, the anti-viral capability of Phytolacca Americana has been recognized. The anti-inflammatory and analgesic qualities of Chaparral (larrea tridentata) have long been acknowledged. Chaparral has been recently shown to be anti-viral and specifically to have efficacy relating to the suppression of Herpes virus replication. Comfrey (symphytum officinale) has long been recognized as a cell proliferator and useful in repairing damaged tissue. Pharmaceutical companies are currently developing derivatives intended for systemic oral and intravenous delivery. While this may be appropriate for the suppression of a systemic viral disease such as AIDS, shingles tends to appear in patches constrained to a relatively small region of the body. Additionally, the virus performs its replication close to the surface of the skin. Consequently, it is the inventor's opinion that the application of systemic anti-virals, such as FAMVIR, causes undue harm by exposing the entire subject's system to the relatively toxic effects that most anti-virals have upon normal organs.
Post Herpetic Neuralgia is pain along the involved nerve, considered by most to be due to the myelin sheath damage that occurred during the initial outbreak. It is the inventor's contention that some of the virus continue to thrive in the Schwann cells which comprise the sheath even after the majority have gone dormant. These remaining virus continue to keep the sheath from being properly repaired and thus extend the period of neuralgia. Since theses cells are not readily accessed by the immune system, continued therapy with systemic anti-viral drugs would be ineffective. The topically applied anti-viral salve described in this patent would diffuse through the tissue and permeate the cells of the nerve sheath killing the virus without immune system support. This is a significant advantage in the treatment of PHN.
A need, therefore, exists for a treatment capable of attacking shingles in an effective manner. The need also exists for a treatment capable of mitigating the adverse conditions following the initial outbreak of shingles, such as, Postherpetic Neuralgia. The present invention provides a method and composition for treating shingles and Postherpetic Neuralgia.